Mitral valve surgery has traditionally been performed through the median sternotomy in which the left atrium of the heart is opened and exposed to allow reconstruction of the mitral valve. More recently, minimally invasive techniques have been used for mitral valve surgery. Minimally invasive techniques are aimed at reducing the amount of extraneous tissue that is damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects.
One minimally invasive mitral valve repair technique is illustrated in FIG. 1. After opening of the atrium, an atrial retractor 100 is used to expose and stabilize the septum to create space for movement of laparoscopic instruments. The atrial retractor 100 includes a retractor blade 102 and a retractor rod 104. The retractor blade is available in different sizes. Typically, blades which are 50 mm long and 25 to 35 mm wide are used. The retractor blade 102 is inserted through a lateral thoracotomy of sufficient size to allow the blade 102 to pass through (e.g., approximately a 3.5 to 5 cm incision). The retractor rod 104 is inserted into the thorax through an incision 108 in the second or third intercostal space just 2 to 3 cm laterally to the sternum in the right chest. The retractor blade 102 is then attached to the retractor rod 104, typically using a screw mechanism.
The atrial retractor is positioned in the right atrium so as to retract the atrial wall to provide satisfactory exposure of the mitral valve annulus and subvalvular structure. The retractor rod 104 is secured in place using a stable structure, such as a holding arm, the operating table, or the patient's chest.
One disadvantage of transthoracic mechanical retractors, such as the atrial retractor 100, is that a thoracotomy is still required in order to introduce the atrial retractor, thereby preventing a fully endoscopic approach to mitral valve repair. In addition, during a robotic assisted mitral valve operation with the da Vinci Surgical System by Intuitive Surgical, Inc. of Sunnyvale, Calif., the insertion of the retractor blade 102, the attaching of the blade 102 and rod 104, and locking and securing of the rod 104 to the holding arm are typically performed while the robotic arm cart is docked to the patient, thereby constraining the workspace for the patient side surgeon. The size of the blade 102 that can be utilized is also limited by space limitations of the thoracotomy and within the patient's body.
Furthermore, the assembly of the retractor 100 is cumbersome and counter-intuitive. The patient side surgeon typically aligns the retractor blade 102 and the rod 104 laparoscopically. If the surgeon is not laparoscopically trained, the assembly time and time to mitral valve exposure can be long and frustrating.
The quality of the mitral valve exposure may vary dramatically from patient to patient, depending on where the retractor rod 104 enters the thoracic cavity. The incision serves as a fixed pivot point for the rigid retractor rod 104, thereby limiting the adjustment of positioning of the retractor blade 102.
In some cases, the retractor rod 104 may collide with the robotic camera arm, thereby decreasing the mitral valve exposure and obstructing the surgeon's view. Moreover, once the retractor 100 is positioned, repositioning later in the procedure may be difficult or impossible. When reposition is possible, the patient side assistant will typically have to perform multiple maneuvers to unlock and readjust the atrial retractor 100, which can be time consuming and cumbersome.
Finally, these retractors may introduce air into the aortic root due to distortion of the aortic valve.
Accordingly, there is a need for an improved retractor which may be used for minimally invasive heart valve repair and other surgical procedures.